Electric lamp



' Dec. 7 1926.v 1,610,062

J. C. LOKKER ET AL v ELECTRIC LAMP Filed Feb. 14. 1923 Inventor's: JanCorneli6 Lokker;

Hendr'iKFi L i o; Pancr'as Schoonenberg; b5 14%; 54::

Their Attorneu Patented Dec-.- 7, 1926. I

UNITED STATES PATENT OFFICE.

JAN coimnms rioxxnn, HENDRIX rrmrro,

novnn, NETHERLANDS, ASSIGNORS TO GENERAL ntnc'rmc comramr, A. oonroaa- TION or NEW YORK.

AND PANCRAS SCHOONENBERG, 0]? E1111)- ELECTRIC LAMP.

Application mm February 14, meg,

to electric I lamps of the white the method "that glass globes with light-diffusing boner glass may be made without this bad effect. This can badone by making glass globes of two layers, which are melted together; the inner layer consists of ordinary clear-glass, whereasthe outer layer is formed of white colored light-difiusmg bone-glass. With a construction above indicated, we have found that the life'ofsuch a lamp is practically the same as that of lamps having globes of the ordinary clear-glass, so that with this invention a considerable improvement is obtained.

In the accompanying drawing a lamp is I illustrated which is provided with a glass globe according to the invention.

The glass globe of the lamp may be of the gas filled type which consists of two layers. The inner layer 1 is of clear-glass, .for example, of a kind ordinarily used in the manufacture of electric light lobes, whereas the outer layer 2 is formed 0 glass of the light-difiusing type preferably of the well known bone-glass.

Inside the globe the glowing body 4 or film is connected to the lead-in wires 5 and 6 which passthrough the glass stem 3 as is usually the case. This stem may be made of the ordinaryelear-glass; As shownin the drawing, the inner part of the lamp is.

completely insulated orseparated from the bone-glass, so' that the prejudicial results which Joecur in lamps using bone-glass as ordinarily constructed do ,not appear in lamps with globes made according to.the invention.

Glass globes for the electric lamps according to the invention may be manufac- Serial No. 618,966, and in the Netherlands February 28, 1922;

tured in accordance with a method which is only slightly more complicated than the method of'manufacture of globes of clearglass alone. According to the invention the lower part ofthe blow pipe with which the globe is blown is first immersed in a bath of ordinary clear-glass, after which it is immersed in a bath of bone-glass. The mass of glass is then blown into aglobe in the ordinary way. In other words, the invention may be practiced by obtaining on the end of'the blow pipe 9. gather of glass which is shaped by rolling over'an iron plate, as is the common practice, to give the mass a definite shape and to cool its surface. This operation is known as marvering. The marvered gather ma dipped into the otherkind of g ass, boneglass for example, a'ndiagain marvered-so as to distribute a' second glass evenly over the-first after which the gather may be blown .in the usual way..

It will be obvious that the invention may be also practiced in connection with automatic glass blowing machines. It isto be observed. that the'globes can be-used for then be electric glow lamps as well as for luminescent lam s, discharge lamps "with tunggether, the inner layer consisting of clearglass and the outer layer of'a light-diffusing glass.

desire to secure An electric lamp having a bulb con sisting of two layers which are melted tosistingo'f two layers which are-melted together, the inner layer consisting of clearglass and the outer layer of a light-diffusing glass, said light-diffusing glass being boneglass.

In witness whereof, we have hereunto setonr hands this thirty-first day of J anuary, 1923.

JAN CORNELIS .LOKKER. HENDRIK FILIPPO. PANCRAS SCHOONENBERG. 

